From High-Throughput Microarray-Based Screening to Clinical Application: The Development of a Second Generation Multigene Test for Breast Cancer Prognosis

Selecting postoperative adjuvant systemic therapy for early-stage breast cancer: An updated assessment and systematic review of leading commercially available gene expression assays

Gene expression assays (GEAs) can guide treatment for early-stage breast cancer. Several large prospective randomized clinical trials, and numerous additional studies, now provide new information for selecting an appropriate GEA. This systematic review builds upon prior reviews, with a focus on five widely commercialized GEAs (Breast Cancer Index®, EndoPredict®, MammaPrint®, Oncotype DX®, and Prosigna®). The comprehensive dataset available provides a contemporary opportunity to assess each GEA's utility as a prognosticator and/or predictor of adjuvant therapy benefit.

Prognostic Cancer Gene Expression Signatures: Current Status and Challenges

Current staging systems of cancer are mainly based on the anatomical extent of disease. They need refinement by biological parameters to improve stratification of patients for tumor therapy or surveillance strategies. Thanks to developments in genomic, transcriptomic, and big-data technologies, we are now able to explore molecular characteristics of tumors in detail and determine their clinical relevance. This has led to numerous prognostic and predictive gene expression signatures that have the potential to establish a classification of tumor subgroups by biological determinants. However, only a few gene signatures have reached the stage of clinical implementation so far. In this review article, we summarize the current status, and present and future challenges of prognostic gene signatures in three relevant cancer entities: breast cancer, colorectal cancer, and hepatocellular carcinoma.

Prognostic Value of EndoPredict in Women with Hormone Receptor-Positive, HER2-Negative Invasive Lobular Breast Cancer

PURPOSE

Invasive lobular carcinoma (ILC) accounts for approximately 5%-15% of all invasive breast cancer cases. Most of the correlations between multigene assays and patient outcome were derived from studies based on patients with invasive ductal carcinoma (IDC) or without distinction between the subtypes. Here, we investigate the prognostic value of EndoPredict (EPclin) in a large cohort of ILCs pooled from three phase III randomized trials (ABCSG-6, ABCSG-8, TransATAC).

EXPERIMENTAL DESIGN

The primary objective of this analysis was to determine the prognostic value of EPclin for distant recurrence (DR) in years 0-10 in postmenopausal women with ILC. The primary outcome was DR.

RESULTS

470 women (17.9%) presented with ILC, 1,944 (73.9%) with IDC, and 216 (8.2%) with other histologic types. EPclin was highly prognostic in women with ILC [HR = 3.32 (2.54-4.34)] and provided more prognostic value than the Clinical Treatment Score [CTS; HR = 2.17 (1.73-2.72)]. 63.4% of women were categorized into the low EPclin risk group and they had a 10-year DR of 4.8% (2.7-8.4) compared with 36.6% of women in the high-risk group with a 10-year DR risk of 26.6% (20.0-35.0). EPclin also provided highly prognostic information in women with node-negative disease [HR = 2.56 (1.63-4.02)] and node-positive disease [HR = 3.70 (2.49-5.50)].

CONCLUSIONS

EPclin provided highly significant prognostic value and significant risk stratification for women with ILC. Ten-year DR risk in the EPclin low-risk groups were similar between ILC and IDC. Our results show that EPclin is informative in women with ILC and suggest that it is equally valid in both histologic subtypes.

Is Axillary Sentinel Lymph Node Biopsy Required in Patients Who Undergo Primary Breast Surgery?

Local treatment of the axilla in clinically node-negative (cN0) early breast cancer patients with routine sentinel lymph node biopsy (SLNB) is debated for various reasons: i) pN staging information may not be necessary for the postoperative treatment decision regarding adjuvant systemic therapy in the great majority of patients; ii) the SLNB-positive rate is declining below 20% in specialized breast centers; iii) albeit being a minimally invasive procedure, SLNB causes a significant reduction in quality of life in 23% of patients; and iv) previous randomized trials from the pre-SLNB era did not show a disadvantage for patients without axillary surgery with regard to overall survival. These data support the hypothesis that avoiding axillary treatment in patients with clinically and sonographically unsuspicious lymph nodes seems to be a safe option, although omitting axillary surgery may increase the risk of locoregional recurrence. Currently, the information regarding node-positive status is essential to guide postoperative treatment such as systemic or radiation therapies in a non-negligible minority of patients. Three ongoing prospective European trials (SOUND, INSEMA, BOOG 2013-08) with axillary observation alone versus SLNB in cN0 patients and primary breast-conserving surgery have the objective to evaluate oncologic safety when omitting SLNB.

Identifying biomarkers to select patients with early breast cancer suitable for extended adjuvant endocrine therapy

PURPOSE OF REVIEW

In this review, we summarize recent and current biomarkers and assays that are being considered in the selection of suitable patients with estrogen receptor-positive early breast cancer for extended (years 5-10) adjuvant endocrine therapy (AET).

RECENT FINDINGS

Women with estrogen receptor-positive early-stage breast cancer (65% of cases) continue to have late risk for distant recurrence extending beyond 5 years from surgery. Recent large trials have consistently demonstrated improvement for prolonging endocrine therapy. However, endocrine therapy can cause women bothersome side effects and can negatively impact quality of life. Determining which patients remain at risk for disease recurrence and predicting which of these patients would derive the most benefit from the addition of extended AET are key issues faced by patients and oncologists today. A number of predictive molecular assays have been developed and are being considered as tools to be used in guiding the implementation of adjuvant systemic therapy.

SUMMARY

The future holds much promise and as more information and understanding is acquired, treatment regimens will increasingly incorporate clinically validated biomarker assays in the decision-making process that will be of great benefit to these patients. Proving clinical utility, though, will ultimately decide their implementation.